• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1339-1344
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• 1998

To develop natural flavoring substances, optimal hydrolysis conditions for two stage enzyme hydrolysates (TSEH) using small kingfish (Maegari) were investigated. The optimal conditions for TSEH were revealed in temperature at $50^{\circ}C$ for 3 hours digestion with alcalase (Aroase AP-10, pH 8.0) at the 1st stage and 2 hours digestion at $45^{\circ}C$ with neutrase (Pandidase NP-2, pH 6.0) at the 2nd stage. From the results in quality tests of water extracts, autolytic extracts and 4 kinds of enzyme hydrolysates, TSEH processing method was superior to other methods on the aspects of yield, nitrogen contents, taste such as umami intensity and inhibition of off-flavor formation, and transparency of extracts. We may conclude that TSEH from small kingfish was more flavorable compared with the conventional seasoning materials, it could be utilized as the seasoning substances for fisheries processing.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.1
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• pp.89-97
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• 2012

Reduction of greenhouse gas (GHG) emissions from upland crop field as well as paddy field is being required, but little information on GHG emissions according to cultivation practices in upland field is available. Soil GHG emissions during the growing season were investigated in the field of three decades rotation and tillage treatments which were consisted of plow, chiesl tillage and no tillage in west central Indiana, USA in 2006. Seasonal cumulative $CO_2$ emissions were not different among treatments. $CH_4$ emission increased a little in plow tillage during early soybean growing season. Most of $N_2O$ emission occurred during early corn growing season after N-fertilizer application from mid June to mid July, and was significantly affected by tillage practices in which seasonal cumulative $N_2O$ emission was significantly higher under chisel tillage. $N_2O$ emission under no-tillage was lower about 64% and 39% than that under chisel tillage and plow tillage, respectively. No-tillage practice with rotation of corn and soybean seems to be promising in point of less GHG emission and less labor for cultivation without grain yield reduction.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.471-477
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• 2013

Biochar amendment to agricultural soil is regarded as a promising option to mitigate climate change and enhance soil quality. It could sequester more carbon within the soil system and increase plant yield by changing soil physicochemical characteristics. However, sustainable use of biochar requires comprehensive environmental assessment. In this sense, it is important to measure additional greenhouse gas emission from soils after biochar addition. We investigated emissions of $CO_2$, $N_2O$, and $CH_4$ from incubated soils collected from rice paddy and cultivated grassland after amendment of 3% biochar (wt.) produced from rice chaff. During incubation, soils were exposed to three wet-dry cycles ranging from 5~85% soil gravimetric water content (WC) to investigate the changes in effect of biochar when influenced by different water levels. The $CO_2$ emission was reduced in biochar treatment compared to the control at WC of 30~70% both in rice paddy and grassland soils. This indicates that biochar could function as a stabilizer for soil organic carbon and it can be effective in carbon sequestration. The $N_2O$ emission was also reduced from the grassland soil treated with biochar when WC was greater than 30% because the biochar treated soils had lower denitrification due to better aeration. In the rice paddy soil, biochar addition resulted in decrease in $N_2O$ emission when WC was greater than 70%, while an increase was noted when WC was between 30~70%. This increase might be related to the fact that available nutrients on biochar surface stimulated existing nitrifying bacterial community, resulting in higher $N_2O$ emission. Overall results imply that biochar amendment to agricultural soil can stabilize soil carbon from fast decomposition although attention should be paid to additional $N_2O$ emission when biochar addition is combined with the application of nitrogen fertilizer.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.105-109
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• 2001

Poorly drained coarse textured paddy soils has harmful substances(e.g. $Fe^{2+}$, $H_2S$, organic acid etc.) due to reduction condition, and lower soil temperature during early stage of rice crop. The roots of the rice plant usually were distributed in the surface layer, and prone to lodged. To solve the problems, the study was carried out in the typical poorly drained, sandy loam textured paddy soils during 1997-1998. Coated urea and urea fertilizers were applied on the surface and whole layer mixed respectively. Yield of the surface fertilization of coated urea had increasing tendency but not significant. Advantages of this experiment was saving of about 30% of nitrogen fertilizer and top dressing labour, which would reduce possibility of water pollution.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.3
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• pp.671-678
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• 2007

Diabetes is a disease in which the body does not produce or properly use insulin. Etiological studies of diabetes and its complications showed that oxidative stress might play a major role. Therefore, many efforts have been tried to regulate free oxygen radicals for treating diabetes and its complications. Gamigukihwandong-hwan has been known to be effective for the treatment of diabetes. The present study was carried out to investigate the effect of Gamigukihwandong-hwan on renal function, peroxynitrite (ONOO$^-$) scavenging activity and polyol pathway in streptozotocin-induced diabetic rats. The crushed Gamigukihwandong-hwan was extracted 3 times, each time with 3 volumes of methyl alcohol at 60$^{\circ}C$ for 24 h. The extract was filtered and evaporated under a reduced pressure using a rotary evaporator to yield 74.95 g. Gamigukihwandong-hwan extract was oral-administered 100 mg per 1 kg of body weight for 20 days to the diabetic rats induced by streptozotocin (60 mg/kg). The effects of Gamigukihwandong-hwan extract on the streptozotocin-induced diabetic rats were observed by measuring the serum level of glucose, insulin, lipid components, creatinine and BUN, and also the kidney levels of superoxide anion radical (${\cdot}O_2^-$), nitric oxide (NO) and ONOO$^-$, and also the enzyme activities involved in polyol pathway. The Effects of Gamigukihwandong-hwan on the streptozotocin-induced diabetic rats with regards to body weight, blood glucose and insulin levels, creatinine and BUN levels, total cholesterol and triglyceride levels, and HDL-cholesterol levels were all shown to be good enough to cure and prevent the diabetes and its complications. Gamigukihwandong-hwan inhibited the generation of ${\cdot}O_2^-$, NO and ONOO$^-$ in the kidney of streptozotocin-induced diabetic rats. Renal aldose reductase and sorbitol dehydrogenase activities were increased in the streptozotocin-induced diabetic rats, whereas the ones in the Gamigukihwandong-hwan administered group among the streptozotocin-induced diabetic rats were reversed toward the natural activities. Gamigukihwandong-hwan might inhibit the development of diabetic nephropathy by scavenging reactive oxygen and nitrogen species, thereby by reducing oxidative stresses and also by regulating the activities of polyol pathway enzymes, all of which could help to recover the function of kidney.

• Journal of Life Science
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• v.23 no.2
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• pp.273-281
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• 2013

The purpose of this research was to investigate the production and characterization of alkaline protease from Micrococcus sp. PS-1 newly isolated from seawater. Micrococcus sp. PS-1 was grown in Luria-Bertani (LB) medium. Its optimal temperature and pH for growth were $30^{\circ}C$ and 7.0, respectively. The effect of nitrogen sources was investigated on optimal enzyme production. A high level of alkaline protease production occurred in LB broth containing 2% skimmed milk. The protease was purified in a 3-step procedure involving ultrafiltration, acetone precipitation, and dialysis. The procedure yielded a 16.43-purification fold, with a yield of 54.25%. SDS-PAGE showed that the enzyme had molecular weights of 35.0 and 37.5 kDa. Its maximum protease activity was exhibited at pH 9.0 and $37^{\circ}C$, and its activity was stable at pH 8.0-11.0 and $25-37^{\circ}C$. The protease activity was strongly inhibited by PMSF, EDTA, and EGTA. Taken together, the results demonstrate that the protease enzyme from Micrococcus sp. PS-1 probably belongs to a subclass of alkaline metallo-serine proteases.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.469-480
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• 2015

The study was conducted on the effects of time of defoliation on fruit quality of pear (Pyrus pyrifolia Nakai) trees, managing with low-pesticides, and regrowth of stem cuttings in vitro. Treatments included for 40% of uniform defoliation at early-August, end-August, and early-September, as well as control (no defoliation). Defoliation at early-September and control increased growth of water sprouts as well as concentrations of carbohydrates, total nitrogen, and free sugar in one-year old shoots. Defoliation at early-September and control increased fruit yield and mean fruit weight, with high soluble solids content and fruit surface color of $a^*$ observed for both defoliation at end-August and early-September. Defoliation at early-August increased rates of electrolyte leakage in stem cuttings at $-18^{\circ}C$ in vitro. There were no significantly different for germination rates of the cuttings between the treatments at -18 and $-21^{\circ}C$ in vitro, with the highest germination of the cuttings observed for defoliation at early-September and control at $-27^{\circ}C$. Therefore, orchard management should be performed to be minimized for defoliation of the spur leaves until end-August, causing from precipitation and pests.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.95-103
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• 2009

To develop natural intermediate flavoring substances, optimal hydrolysis conditions and taste compounds for two step enzyme hydrolysate(TSEH) using Grass puffer(Takifugu niphobles) were investigated. The optimal conditions for TSEH method were revealed in temperature at $55^{\circ}C$ 3 hour digestion with Alcalase (pH 7.5) at the 1st step and 2 hour at $45^{\circ}C$ digestion with Flavourzyme(pH 6.0~6.5) at the 2nd step. TSEH method was superior to hot-water extraction on the aspect of yield, nitrogen contents and organoleptic taste quality such as umami and control of bitter taste formation. In taste active-components in Glass puffer TSEH, total free amino acid content was 4,502 mg%, major free amino acids were Pro, Leu, Lys, Hypro, Tau, Arg, Phe, Ala, Glu and Val in ordor. As for nucleotides, IMP(372 mg%) was the principal component and also contents of TMAO, total creatinine, and betaine were 43, 278 and 41 mg% in Glass puffer TSEH, respectively. The major inorganic ions in TSEH were Na(949 mg%), K(222 mg%), Cl(1,180 mg%) and $PO_4$(1,081 mg%).

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.452-456
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• 2011

Glomalin has important roles in soil aggregation in agricultural lands including controlled horticultural lands. The objective of this study was to measure total glomalin content of soils treated conventional farming system (CFS), conventional farming system without pesticides (CFSWP), and organic farming system (OFS) for strawberry cultivation under greenhouse in Goseong-gun, Korea. The average concentration of total glomalin in the soils was significantly higher in the OFS ($2.00mg\;g^{-1}$) compared to the CFS ($1.68mg\;g^{-1}$). In addition, soil microbial biomass C content was 4.9 times higher in the OFS ($821mg\;kg^{-1}$) compared to the CFS ($169mg\;kg^{-1}$). Nitrogen uptake rate of strawberry was higher in the OFS (52.4%) than that in the CFS (13.0%). Furthermore, yield of strawberry in OFS ($51Mg\;ha^{-1}$) was significantly higher compared to CFS ($35Mg\;ha^{-1}$).

• Journal of Mushroom
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• v.19 no.3
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• pp.160-165
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• 2021

This study was conducted to investigate a suitable substrate formulation for bag cultivation of Hypsizygus marmoreus. To determine the optimum media composition for H. marmoreus, chemical properties of various media and culture properties were investigated. The fastest primordia formation (9.0 days), the shortest fruiting body harvest period (18.0 days), and the highest yield (144.7 g/bag) were realized with the T6 formulation (55:15:20:5:5 mixing ratio of poplar sawdust, wheat bran, rice bran, dried soybean powder, and palm kernel, respectively). The chemical properties of the T6 formulation were pH, 6.0; total carbon, 19.0%; total nitrogen, 0.83%; C/N ratio, 22.8; P₂O₅, 0.61%; K₂O, 0.46%; and MgO, 0.29%. This is the first attempt using plastic bags for cultivation and will help expand the production of H. marmoreus.